The invention relates to an apparatus for preventing fluid spray at leakage areas of a fluid pipe, to the use of such apparatus, and to an aircraft comprising at least one item of the apparatus for preventing fluid spray at leakage areas of a fluid pipe.
Below, aspects of the invention relating to hydraulic fluids and to their use in commercial aircrafts are described. However, this is to be understood only in an exemplary manner. The aspects of the invention may be transferred to other types of fluid pipes. Likewise, the use is not limited to aircrafts; instead, any fluid pipes that have been installed so as to be stationary, or that have been installed in whatever type of vehicles or equipment with sensitive regions, could be considered.
In today's commercial aircrafts, hydraulic systems are frequently used in order to handle a variety of tasks, for which hydraulic systems with multiple hydraulic fluid pipes are required. The pressure level within these pipes ranges up to 350 bar. If damage to a hydraulic fluid pipe occurs, be it as a result of selective corrosion or pitting, or as a result of a fracture, hydraulic fluid may issue. In major leakages, a fluid jet may form which diffuses fluid into the space surrounding the hydraulic fluid pipe. In this context, it may happen that sensitive equipment or apparatus is exposed to hydraulic fluid and is possibly damaged as a result of this exposure. In addition, the impact of the emanating hydraulic fluid jet may result in local sprinkling or spraying of the hydraulic fluid jet, which results in additional large-area soiling of the region concerned. Depending on the general conditions, a leakage could result in the spraying of hydraulic fluid already at the point where it issues, and consequently a large region around the leakage area could become soiled.
Apart from the danger of soiling or damaging equipment or apparatus in a sensitive region, in the case of the spraying of a hydraulic fluid, there is also a danger of a combustible air/hydraulic fluid mixture forming, which would jeopardise safe operation of the aircraft.
In the state of the art, there is equipment that is used to protect against leakages or soiling when leakages do occur. It is known to use a protective shield between a potential leakage area and the surroundings to be protected. However, this requires sufficient design space and sufficient knowledge as to the positions at which, for example, a hydraulic fluid pipe might develop a leak.
German patent application no. DE 102004021245 A1 and U.S. patent application publication no. 2007/0200031 A1 disclose apparatus to protect against leakages, which apparatus is in the form of an arrangement comprising a pipe and a protective tube. The protective tube fully encloses the pipes so that in the case of a leak in the pipe the conveyed liquid is retained in the protective tube rather than issuing into the surroundings. However, this device is designed for use on fuel lines in aircraft, which fuel lines only have a pressure level of a few bar. Due to the high pressure level, the use with hydraulic fluid pipes would be uneconomical, because the apparatus would have to be massive, heavy and cost-intensive.